Inside a vehicle, there provided a room mirror for watching the area behind. In recent years, room mirrors, TV cameras and others may be provided in the automobiles in order to improve the functions of automobiles. These accessories are attached to a part of the room, e.g., a wall, an instrument panel, etc. These accessories have the structure that they come off the installed location at the impact of a collision or other cases in order to prevent the accessories from damaging when the passenger's head hit it and large impact is applied thereto. However, under normal condition, the accessory is retained so that the accessory does not easily come off the installed location, and the accessory comes off only when an exceeding impact is applied thereto.
There is an assembly disclosed in Japanese Patent Laid-open No. HEI 7-61286 as an example of the conventional room accessory retaining apparatus having the above structure. This assembly comprises a base attached, e.g., to a car window. There is a retainer made of elastic member having two parallel retaining arms at the base, and the retainer elastically retains a coupler. The coupler has a long conic protrusion provided, and the retainer retains the coupler by inserting the protrusion. Then, the rearview mirror assembly retains by connecting the stay to the coupler.
Further, in order to install the base to the coupler, the coupler slides on the base so that the protrusion of the coupler is inserted in the two parallel retaining arms of the retainer. Next, the coupler is rotated and then since the protrusion is long conical, the retaining arms are pressed in the direction opposite to the base. Then, at this point, the retaining arms compress the retainer and the protrusion of the coupler is pressed to the base. In the above-described manner, the coupler is installed to the retainer so that the rearview mirror assemblies are retained by the base.
In such an assembly, the retaining apparatus can be constituted with small number of members such as a base, a coupler and a retainer. Further, in a case that the impact is applied to the side of the rearview mirror body, the coupler is rotated and the compression of the retainer is eliminated, and the coupler comes off the base. Further, in a case that the impact is applied to the rearview mirror assemblies from the front, the coupler is moved in the direction opposite to the direction that the coupler is inserted into the base and then the coupler comes off the base. In such ways, the coupler easily comes off the base using a rotation mode in a case of an impact from the side and a sliding mode in a case of an impact from the front. Accordingly, such assemblies are superior in releasing the impact and in preventing the static action.
However, in the assemblies disclosed in the above document, when the rearview mirror assemblies come off in the sliding mode, the coupler is moved in the direction opposite to the moving direction that the coupler is attached to the base. In this case, for example, when the retaining force for the rearview mirror assemblies is large, the minimum force for the rearview mirror assemblies coming off needs to be small. Therefore, the impact that the rearview mirror assemblies are released cannot be controlled unrelated with the retaining force for the rearview mirror.
It is an object of the present invention to provide a room accessory retaining apparatus capable of controlling the retaining force for an accessory unrelated with the impact that the accessory comes off in the sliding mode.